Peptides zinc-binding

Independently, Ruan etal. (1990) demonstrated that unnatural metal-ligating residues may likewise be utilized toward the stabilization of short a helices by transition metal ions (including Zn " ")—these investigators reported that an 11-mer is converted from the random coil conformation to about 80% a helix by the addition of Cd at 4°C. These results suggest that the engineering of zinc-binding sites in small peptides or large proteins may be a powerful approach toward the stabilization of protein secondary structure. 

The engineering of zinc-binding sites in a-helical peptides, where metal binding stabilizes protein tertiary structure, has been reported by Handel and DeGrado (1990). In these experiments zinc-binding sites are incorporated into a dimeric helix-loop—helix peptide (H3 2) and a protein composed of four helices connected by three short loop sequences (H3 4). a model of one subunit of the H3 2 dimer is found in Fig. 47. In addition to metal complexation by two histidine residues at positions n and n+4 of one a helix, the metal is coordinated by a third histidine residue of an adjacent a helix. The composition of the zinc coordination polyhedron is like that of carbonic anhydrase (i.e., Hiss), and spectroscopic results suggest that all three histidine residues are involved in zinc complexation. This work sets an important foundation... 

TPR (Tetratrico peptide repeat)247,275,276 ZBD (Zinc-binding domains) Zinc finger (Fig. 5-37)277 Others277-280 ... 

Melino, S., Rufini, S., Sette, M., Morero, R., Grottesi, A., Paci, M. et al. (1999) Zn2+ ions selectively induce antimicrobial salivary peptide Histatin-5 to fuse negatively charged vesicles. Identification and characterization of a zinc-binding motif present in the functional domain. Biochemistry, 38, 9626-9633. 

Fitzsimons MP, Barton JK. Design of a synthetic nuclease DNA hydrolysis by a zinc-binding peptide tethered to a rhodium inter-calator. J. Am. Chem. Soc. 1997 119 3379-3380. 

The overall structures of all MMP catalytic domains known so far are very similar (Fig. 2). These MMP catalytic domains are shaped like an oblate ellipsoid, with a small active-site cleft, harboring the catalytic zinc ion, notched into the flat ellipsoid surface. The active site cleft is defined by helix hB, which provides two histidine residues that coordinate to the catalytic zinc ion, and the catalytic Glu in between, all belonging to the zinc-binding consensus sequence HEYZHYZGXZH (5, 22, 23). The active-site helix ends at a Gly residue, where the peptide chain bends, presenting the third zinc-liganding His. The zinc ion also coordinates to a water molecule that... 

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